string pattern

[hoai linh]

Hello,
I have following code:

        String str = "Sally sells seashells by the seashore";
        Pattern pattern = Pattern.compile("(\\b\\w{5}).*\\1");
        Matcher matcher = pattern.matcher(str);
        System.out.println(matcher.find());

and the ouput is "true"! For the words "Sally", "sells" and "seashells" I can understand that they match the pattern. But the words "by" and "the", they don't match the pattern and the output is true, why?? Can anybody explain it? Thank you very much!

Linh

[Matthew Brown]

What do you think that pattern is looking for, then?

[Jelle Klap]

The pattern matches a word boundry, followed by exactly 5 word characters - this combined forms a capture group - followed by any character 0 (zero) or more times greedily, followed by a repeat of the first capture group (a word boundy followed by exactly the same 5 word characters).
Apply this logic to the speified String literal, and it should make sense.